I'm going to upgrade from the UE TF10 in a few weeks and was wondering what are the best current IEMs with the "Etymotic" type flat/neutral sound. I've tried my roommate's ER6i and greatly preferred its neutral sound and great clarity in comparison to the TF10's sound. To me, the ER6i has almost perfect bass; the bass sounded really tight and defined; however, a little more bass would also be fine, but not to the levels of the TF10.
I've been researching primarily the ER4P, HF5, and RE0. Though the ER4P have the 'matched' armatures, I think I would prefer the HF5 as most say it is more comfortable and has comparatively less microphonics. The RE0 is not an option, as I'm not impressed by the build quality and that it has less isolation than the Etymotics.
So, for a max budget of $200US, what would be the other alternatives to consider (versus the Etymotic HF5)? - neutral sound, solid build quality, great isolation, unamped usage